Recent measurements of the mean luminosity density contributed by
high surface brightness galaxies at moderately low
redshift are summarized in Table 2. There is a
substantial spread of estimates of the parameters
* and
M* in the Schechter function,
but the total luminosity density,
= *L*( + 2), is better
defined:
most values are in the range
B =
(1.8-2.2) x 108hL Mpc-3.
The exception is the significantly lower number from the APM-Stromlo
survey
(Loveday et al. 1992).
We adopt

(4)

The second expression is the corresponding value of the
mass-to-light ratio in the Einstein-de Sitter model.